/*
 * Copyright 2002-2014 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.transaction;

/**
 * Interface that specifies an API to programmatically manage transaction
 * savepoints in a generic fashion. Extended by TransactionStatus to
 * expose savepoint management functionality for a specific transaction.
 *
 * <p>Note that savepoints can only work within an active transaction.
 * Just use this programmatic savepoint handling for advanced needs;
 * else, a subtransaction with PROPAGATION_NESTED is preferable.
 *
 * <p>This interface is inspired by JDBC 3.0's Savepoint mechanism
 * but is independent from any specific persistence technology.
 *
 * @author Juergen Hoeller
 * @see TransactionStatus
 * @see TransactionDefinition#PROPAGATION_NESTED
 * @see java.sql.Savepoint
 * @since 1.1
 */
public interface SavepointManager {

    /**
     * Create a new savepoint. You can roll back to a specific savepoint
     * via {@code rollbackToSavepoint}, and explicitly release a savepoint
     * that you don't need anymore via {@code releaseSavepoint}.
     * <p>Note that most transaction managers will automatically release
     * savepoints at transaction completion.
     *
     * @return a savepoint object, to be passed into
     * {@link #rollbackToSavepoint} or {@link #releaseSavepoint}
     * @throws NestedTransactionNotSupportedException if the underlying
     * transaction does not support savepoints
     * @throws TransactionException if the savepoint could not be created,
     * for example because the transaction is not in an appropriate state
     * @see java.sql.Connection#setSavepoint
     */
    Object createSavepoint() throws TransactionException;

    /**
     * Roll back to the given savepoint.
     * <p>The savepoint will <i>not</i> be automatically released afterwards.
     * You may explicitly call {@link #releaseSavepoint(Object)} or rely on
     * automatic release on transaction completion.
     *
     * @param savepoint the savepoint to roll back to
     * @throws NestedTransactionNotSupportedException if the underlying
     * transaction does not support savepoints
     * @throws TransactionException if the rollback failed
     * @see java.sql.Connection#rollback(java.sql.Savepoint)
     */
    void rollbackToSavepoint(Object savepoint) throws TransactionException;

    /**
     * Explicitly release the given savepoint.
     * <p>Note that most transaction managers will automatically release
     * savepoints on transaction completion.
     * <p>Implementations should fail as silently as possible if proper
     * resource cleanup will eventually happen at transaction completion.
     *
     * @param savepoint the savepoint to release
     * @throws NestedTransactionNotSupportedException if the underlying
     * transaction does not support savepoints
     * @throws TransactionException if the release failed
     * @see java.sql.Connection#releaseSavepoint
     */
    void releaseSavepoint(Object savepoint) throws TransactionException;

}
